Telecommunications apparatus using a first random access procedure and a second random access procedure

1. A method of transmitting data in a telecommunications system comprising a terminal and a base station, the terminal configured to use a first random access procedure and a second random access procedure for the transmission of the data to the base station, wherein according to the first random access procedure, the terminal initiates the first random access procedure by transmitting a message comprising the data and a random access preamble, and according to the second random access procedure, the terminal only transmits the data after receiving a random access response, the method comprising:

transmitting, by the terminal in a case that a size of the data is below a threshold, a first random access request message to the base station in accordance with the first random access procedure, the first random access request message comprising at least part of the data and a first preamble;

determining, by the terminal, whether transmission of the first random access request message in accordance with the first random access procedure has been unsuccessful; and

transmitting, by the terminal in a case that the determining indicates that the transmission in accordance the first random access procedure has been unsuccessful and in a case that the size of the data is above the threshold, a second random access request message to the base station in accordance with the second random access procedure, the second random access request message comprising a second preamble, wherein

the terminal determines that the first random access procedure is unsuccessful in a case that the terminal receives an indicator from the base station, the indicator instructing the terminal to transmit in accordance with the second random access procedure.

2. The method of claim 1 , wherein the first preamble is selected from a first group of preambles and the second preamble is selected from a second group of preambles different from the first group of preambles.

3. The method of claim 1 , wherein the determining whether the first random access procedure has been unsuccessful is further based on the terminal failing to receive a response to the first random access request message within a time window.

4. The method of claim 1 , further comprising:

determining, by the base station, that the network is experiencing a high level of load; and

responding, by the base station upon determining that the network is experiencing a high level of load, to the first random access request message with a random access response message comprising the indicator.

5. The method of claim 1 , further comprising:

determining, by the base station, that the at least part of the data in the first random access request message could not be decoded; and

responding, by the base station upon determining that the at least part of the data could not be decoded, to the first random access request message with a random access response message comprising the indicator.

6. The method of claim 3 , wherein

the indicator comprises waiting time information, and

the method further comprises, upon receipt of the indicator, the terminal waiting a certain time based before transmitting the second random access request message, the certain time based on the waiting time information.

7. The method of claim 1 , further comprising:

determining, by the terminal, to send the first random access request message in accordance with the first random access procedure when the size of the data is below the threshold; and

determining, by the terminal, to use the second random access procedure when the size of the data is above the threshold.

8. The method of claim 1 , further comprising:

determining, by the terminal, that the first random access procedure has been unsuccessful when a number of unsuccessful transmission of random access messages to the base station in accordance with the first random access procedure has reached a predetermined number of attempts.

9. A terminal for transmitting data in a telecommunications system including a base station that is configured to receive transmissions via a first random access procedure and a second random access procedure, wherein according to the first random access procedure, the first random access procedure is initiated by transmission of a message comprising the data and a random access preamble, and according to the second random access procedure, transmission of the data is permitted only after reception of a random access response, the terminal comprising:

a transceiver; and

circuitry configured to

control the transceiver to transmit, in a case that a size of the data is below a threshold, a first random access request message to the base station in accordance with the first random access procedure, the first random access request message comprising at least part of the data and a first preamble;

determine whether transmission of the first random access request message in accordance with the first random access procedure has been unsuccessful; and

control the transceiver to transmit, in a case that the circuitry determines that the transmission in accordance with the first random access procedure has been unsuccessful and in a case that the size of the data is above the threshold, a second random access request message to the base station in accordance with the second random access procedure, the second random access request message comprising a second preamble, wherein

the circuitry determines that the first random access procedure is unsuccessful in a case that the transceiver receives an indicator from the base station, the indicator instructing the terminal to transmit in accordance with the second random access procedure.

10. The terminal of claim 9 , wherein the first preamble is selected from a first group of preambles and the second preamble is selected from a second group of preambles different from the first group of preambles.

11. The terminal of claim 9 , wherein the circuitry further determines whether the first random access procedure has been unsuccessful based on the terminal failing to receive a response to the first random access request message within a time window.

12. The terminal of claim 11 , wherein

the indicator comprises waiting time information, and

the circuitry is further configured to, upon receipt of the indicator, wait a certain time based before controlling the transceiver to transmit the second random access request message, the certain time based on the waiting time information.

13. The terminal of claim 9 , wherein the circuitry is further configured to

determine to control the transceiver to transmit the first random access request message in accordance with the first random access procedure when the size of the data is below the threshold, and

determine to use the second random access procedure when the size of the data is above the threshold.

14. The terminal of claim 9 , wherein the circuitry is further configured to determine that the first random access procedure has been unsuccessful when a number of unsuccessful transmission of random access messages to the base station in accordance with the first random access procedure has reached a predetermined number.

15. Circuitry for a terminal that transmits data in a telecommunications system including a base station that is configured to receive transmissions via a first random access procedure and a second random access procedure, wherein according to the first random access procedure; the first random access procedure is initiated by transmission of a message comprising the data and a random access preamble, and according to the second random access procedure, transmission of the data is permitted only after reception of a random access response, the circuitry comprising:

a transceiver circuit; and

a control circuit configured to:

control the transceiver circuit to transmit, in a case that a size of the data is below a threshold, a first random access request message to the base station in accordance with the first random access procedure, the first random access request message comprising at least part of the data and a first preamble;

determine whether transmission of the first random access request message in accordance with the first random access procedure has been unsuccessful; and

control the transceiver circuit to transmit, in a case that the control circuit determines that the transmission in accordance with the first random access procedure has been unsuccessful and in a case that the size of the data is above the threshold, a second random access request message to the base station in accordance with the second random access procedure, the second random access request message comprising a second preamble, wherein

the control circuit determines that the first random access procedure is unsuccessful in a case that the transceiver circuit receives an indicator from the base station, the indicator instructing the terminal to transmit in accordance with the second random access procedure.